1. Field of the Invention
The invention concerns a radar device with a planar antenna comprising grouped individual radiating devices for object self-protection against the threat from an attacking missile.
2. Discussion of the Prior Art
A radar device of that kind is known from DE 28 22 845 C2 in the form of a group antenna with electronically controlled beam sweep for panoramic scanning in order to be able to detect an approaching in-flight attacker at least in terms of the direction of attack but as far as possible also in respect of the instantaneous attack speed and range, and to be able to appropriately direct defence equipment. The preference there is for the arrangement of individual radiating devices in a spherical volume, over an arrangement in the form of planar group antennae which are rejected as being inappropriate because their beam focusing characteristics, because of varying projection on to the group arrangement, depend on the instantaneous sweep direction and also, with the usual arrangements, their focusing is markedly less sharp in the horizontal direction than in the vertical direction. However even when individual radiating devices are arranged in a staggered configuration in the form of a spherical shell, that still involves the problems of providing for an arrangement, which is mechanically stable in terms of vibration and oscillation, of the spherical structure which stands up high, on the object when it is moving over rough terrain, and functionally critical interfaces between the object which carries such a radar device and the defence equipment which is to track the approaching in-flight attacker in a highly dynamic manner, for self-protection of the object. A particular bottleneck is the sufficiently fast echo evaluation of the very large number of individual radiating devices, having regard to their current geometrical configuration, in relation to the attacker which is approaching very fast and close.
Therefore the object of the present invention is to provide a radar device of the general kind set forth, which with simple, tried-and-tested technology, is suitable in particular for fast aiming and tracking of a launch container with fragmentation shells or projectiles against the approach flight of a remotely controlled or self-steering missile to a short residual distance, as is described as a self-protection system in U.S. Pat. No. 5,661,254 A or in DE 199 51 915.3 of Oct. 28, 1999, which has not yet been published (reference is made thereto in respect of full content herein to supplement the description of the invention set forth hereinafter, for the avoidance of repetition).
In accordance with the invention set forth in the main claim, to attain that object, recourse is had to the planar antenna which is expressly rejected precisely for such functions in the prior publication relating to the general kind of device involved. It is now arranged as a frequency-scanning monitoring radar directly on the substructure, which is fixed with respect to the object, of the aiming drive for the launch container and is modularly so dimensioned that its aiming characteristic which is pivotable immaterially through about xc2x190xc2x0 scans in Doppler-sensitive fashion practically half the azimuth ahead with moderate azimuth direction-finding sharpness but a high degree of elevational direction-finding sharpness. That affords information which admittedly is initially only rough but which is fast, relating to the instantaneous approach co-ordinates of an attacker and the motion data thereof, in order to orient the launch container with its defence fragmentation projectiles in that direction. Now, in the determined segment of space, additional high-resolution target-tracking radar comes into operation for precise target acquisition and tracking in order to direct the operative direction of the launch container to the target and thereafter to launch the projectiles in the optimum approach situation.
For that purpose the target-tracking radar, designed for example in the form of a mono-pulse system, is integrated in axis-parallel relationship directly into the launch container. As a result there is no need for the procedure, which is demanding in terms of computing power and critical in respect of time, of converting the target direction co-ordinates and transferring them from the tracking system to the directional control of the launch container. On the contrary, the attacker is interpreted as the target in accordance with the rough vectoring from the monitoring radar directly in the operative direction of the defence projectiles, the target then being tracked with the launch container in a fine tracking procedure. The launch system would in any case have to be oriented towards the target. Therefore, combining together in terms of apparatus target acquisition of the launch arrangement and the tracking radar, in accordance with the invention, affords a time saving and simplified control parameters. This means that the control member for the directional drives of the launch container is acted upon directly firstly by the monitoring radar and thereafter by the target-tracking radar, without first having to transform co-ordinate systems. That therefore inevitably affords an ideal kinematics because the operative direction of the launch container directly follows the target movement relative to the object to be protected in order to provide that, when an operatively optimised spacing for the function of the defence fragmentation projectiles is reached, they are fired off against the target which has long been acquired.